Abstract: Provided is a nonaqueous electrolyte secondary battery laminated separator that makes it possible to reduce an increase in alternating-current resistance after compression. A nonaqueous electrolyte secondary battery in accordance with an embodiment includes: a nonaqueous electrolyte secondary battery functional layer; and a polyolefin base material, the nonaqueous electrolyte secondary battery functional layer and the polyolefin base material being formed on top of each other, after the nonaqueous electrolyte secondary battery laminated separator is subjected to pressure application at 20 MPa, the nonaqueous electrolyte secondary battery functional layer having a compressibility of not less than 15%, and the polyolefin base material having a compressibility of not more than 5%.

Abstract: Provided is a nonaqueous electrolyte secondary battery functional layer that makes it possible to achieve an enhanced high-rate discharge capacity after pressure application. A nonaqueous electrolyte secondary battery functional layer in accordance with an embodiment is configured such that: the nonaqueous electrolyte secondary battery functional layer has an internal void volume of not less than 2.5 mL/m2; and the nonaqueous electrolyte secondary battery functional layer has a surface having an uneven space volume of not less than 0.5 mL/m2.

Abstract: A nonaqueous electrolyte secondary battery functional layer makes it possible to achieve lower electrode resistance after pressure application. A nonaqueous electrolyte secondary battery functional layer in accordance with an embodiment of the disclosure has an area ratio of pores satisfying all of the following conditions 1 to 3 of not less than 3% by area with respect to all pores present in a cross section of the nonaqueous electrolyte secondary battery functional layer, the condition 1 being that a maximum Feret diameter is not less than 0.5 ?m, the condition 2 being that an angle at which a pore takes on the maximum Feret diameter is 60° to 120° with respect to an in-plane direction of the nonaqueous electrolyte secondary battery functional layer, and the condition 3 being that the maximum Feret diameter/a minimum Feret diameter has a value of not less than 1.2.

Abstract: Provided is a nonaqueous electrolyte secondary battery laminated separator that makes it possible to achieve both maintenance of sufficient air permeability and maintenance of voltage resistance during compression. A nonaqueous electrolyte secondary battery laminated separator in accordance with an embodiment includes: a nonaqueous electrolyte secondary battery functional layer; and a polyolefin base material, the nonaqueous electrolyte secondary battery functional layer and the polyolefin base material being formed on top of each other, wherein the nonaqueous electrolyte secondary battery functional layer contains a filler, the filler that has a particle diameter of not less than 0.1 ?m has a volume fraction of not less than 15% by volume in the nonaqueous electrolyte secondary battery functional layer, and a ratio of contact between the polyolefin base material and the filler that has a particle diameter of not less than 0.1 ?m is not more than 7%.

Abstract: Provided is a nonaqueous electrolyte secondary battery functional layer that has an improved cycle characteristic when an electrode with a great change in volume is used. A nonaqueous electrolyte secondary battery functional layer in accordance with an embodiment of the disclosure is configured such that an area ratio of pores each having a cross-sectional area of not less than 0.1 ?m2 is not less than 30% by area with respect to all pores present in a cross section of the nonaqueous electrolyte secondary battery functional layer.

Abstract: Provided is a nonaqueous electrolyte secondary battery functional layer that makes it possible to reduce an increase in air permeability (Gurley value) during compression. A nonaqueous electrolyte secondary battery functional layer in accordance with an embodiment contains a first filler and a second filler, the first filler having an average particle diameter of not more than 0.03 ?m, and the second filler having an average particle diameter of not less than 1 ?m.

Abstract: Provided is a nonaqueous electrolyte secondary battery laminated separator that makes it possible to reduce a reduction in discharge capacity after cycles even in a state in which the nonaqueous electrolyte secondary battery laminated separator is compressed.

Abstract: As a nonaqueous electrolyte secondary battery porous layer that is excellent in durability with respect to charge-discharge cycles, provided is a nonaqueous electrolyte secondary battery porous layer including a resin which has an amide bond and which contains a component that is to be eluted into N-methylpyrrolidone. A contained amount of the component that is to be eluted into N-methylpyrrolidone is not less than 6.0% by weight and not more than 25.0% by weight relative to a total weight of the resin having the amide bond.

Abstract: An inspection method with which a separator having improved quality can be efficiently obtained is provided. The inspection method is a method for inspecting a nonaqueous electrolyte secondary battery separator that includes a polyolefin porous film. The inspection method includes a step of detecting a defect in the polyolefin porous film with the use of a color camera.